Paper product and method of making the same



Patented May 5, 1931 UNITED STATES/PATENT OFFICE HAROLD ROBERT RAITON, OI RA'WRE'NCE, MASSACHUSETTS, ASBIGNOR TO RAI'II'OLD PROCESS CORPORATION, A. OORYOBATION OF MASSACHUSETTS PAPER PIRDDUOT AND METHOD MAKING THE SAME No Drawing.

This invention relates to the manufacture of paper and more particularly to an imroved sized paper containing a carbonate iiller and a method of making the same. The principal object of this invention is to provide a process of sizing paper made with a carbonate filler wherein parafiin is employed as the sizing agent, the paraifin being emplo ed in the form of a substantlally nonbreaka le emulsion, the disperse phase of such emulsion being concentrated by the mutual precipitation or flocculation of two suitable precipitating agents in the presence of the emulsion.

An important object of this invention is to provide an economical and efficient process of making an im roved sized paper made with a carbonate ller wherein the disperse phase of a substantially nonbreakable parafzo fin emulsion is concentrated b the mutual recipitation or flocculation 0 sodium resmate and alum.

Another object of this invention is to provide a simple and efficient process of making 26 an improved sized paper made with a carbonate filler wherein a substantially nonbreakable paraflin emulsion is employed as a sizing agent and wherein two mutual precipitating ents are employed for concentrat- 80 ing the isperse phase of the paraffin emulsion, the sizing effect of the sizing agent which is wholly or in part deteriorated by the action of the carbonate filler employed being restored by the subsequent addition of a sultable sizin restoring agent.

A further object of this invention is to provide a paper making process of the above referred to character wherein sodium resinate and alum are emplo ed for concentrating the disperse phase of t e paraffin emulsion employed and wherein alum is employed as a sizin restoring agent.

Ot er objects and advantages of this invention will become ap arent during the course of the following escription.

In my copending application Serial No. 304,169 filed Sept. 5, 1928, I have described a method of using a substantially nonbreakable parafiin emulsion as a sizing agent in the 50 manufacture of paper wherein the mutual Application filed September 5, 1828. Serial No. 804,170.

flocculation of two suitable reacting a entssuch as sodium resinate and alum is em oyed to concentrate the disperse phase 0? such emulsion and brin it into association with the fibre cmploye The method of sizing described therein refers to pa or made without filler or with ordinary V 11ers such, for example, as clay or talc. The present invention relates to the similar use of a substantially nonbreakable parafiin emulsion as sizing for papers which contain carbonate fillers. In this case it is found that the carbonate fillers cause deterioration of the sizing I effect when used in the place of ordinary fillers such as clay for example, and the meth- 0d of circumventing this deterioration of sizing by the carbonate filler by the expedient of'restoring the sizing with a suitable agent after the deterioration of the sizing has taken place is dealt with herein. An analo ous method is disclosed in my copending app ication Serial No. 304,168 filed Sept. 5, 1928, for use when rosin size is the sizing agent employed.

As will be apparent to those skilled in the art, it is substantially the universal practice in sizing paper to mix with suitable fibrous materials and filler, if such is to be employed, sodium resinate, and to precipitate the sodium resinate with alum in the presence of 80 the fibre. While the order of addition of these ingredients may be and is varied in different processes it has been generally accepted that the addition of both sodium resinate and alum, or equivalent thereof, is necessary for imparting suitable sizing to the finished paper. As is well known, the socalled sodium resinate employed in paper making processes is not always this exact I compound nor, when this compound is used, is it necessarily chemically pure, it generally containing varying amounts of uncombined rosin and sometimes uncombined alkali. However, where this term is employed herein it is to be understood that the term includes any material produced by the action of alkali, generally in aqueous solution, on rosin, or on natural or s nthetic resin acid or acids, regardless of t e exact composition of the prod- I.

not or the varying composition which different samples of the product may possess.

Sized paper made substantially in accordance with the eneral method outlined above is not suitable for many purposes and various ther types of papers are employed in numerous arts. For example, it has been proposed heretofore to make a water resistant paper by adding to suitable fibre a combination of sodium resinate and a breakable parafiin emulsion, ordinarily a saponaceous emulsion, and to precipitate the paraffin in connection with the rosin 011 the fibrous material by the use of alum. Paper of this class is commonly called. paraflined paper.

While paraflined papers are suitable for many uses the use of such papers is not general. For example, these papers generally have a araflin finish which makes them substantial y waterproof and are ordinarily translucent or substantially transparent. Hence such papers are not suitable for use as book, magazine, writing or printing paers. p Moreover the use of emulsions particularly of the class referred to above which are employed in making paraiiined papers is attended with numerous serious disadvantages as hereinafter more particularly set forth. As is well known an emulsion of paraflin is a suspension of microscopically minute particles of paraflin in a liquid, ordinarily aqueous or miscible with water, containing an emulsifying agent, i. e., a material or materials which tend to prevent the coalescence of the individual particles of paraflin. The most widely accepted work relating to emulsions points to the fact that there is actually a layer or film of the emulsifying agent one or more molecules in thickness surrounding each particle of emulsified material, which in the case of paraflin is called herein the disperse phase of the emulsion. This film or layer however in certain cases may be of very much greater thickness, for instance in the case where an insoluble emulsifying agent is used. The individual particles of the disperse phase of an emulsion act very differently from the same material in comminuted form in an aqueous medium in which no emulsifying a ent is present. In such case the individua particles are not prevented from contacting with each other and in fact the particles do touch and eventually coalesce to form relatively massive lumps of the material. The same material in emulsified form however does not have these characteristics and the individual particles of the disperse phase, such as parafim, for example, are prevented from touching one another with the result that there is no tendency for the particles to coalesce and form lumps. Although particles in unemulsified condition exhibit different characteristics from similar particles in emulsified condition it is to be pointed out that different emulsions differ in several respects but particularly do they differ with regard to their stability. For example man and undoubtedl the great majority of emu sions tend to reso ve or break in the well known manner. It is this characteristic that has led chiefly to the disadvantages surrounding the use of emulsions in paper making processes as heretofore employed. For example, certain emulsions commonly employed for use in pa er making such for example as paraffin emu sions are broken by the addition of alum thereto. Moreover, such emulsions can usuall be broken by acids and also to some extent y soluble salts such as those which occur in hard water or. incompletely washed fibrous materials. This breaking of emulsions such as a paraffin emulsion is accompanied by the rise of the individual particles such as paraffin which are released from the emulsified form, to the surface of the liquid with consequent tendency toward agglomeration and formation of relatively large particles.

When breakable emulsions" of the character referred to have been employed heretofore in paper making processes the paraflin has been precipitated in individual particles usually by alum on the fibre while the fibre was in aqueous suspension. In some cases sodium resinate has been employed in connection with such breakable emulsions and the mixture of the sodium resinate and paraflin emulsion has been mutually recipitated on the fibre by means of alum. f course, in this case as well as in the case where no sodium resinate was employed the paraffin was deposited in individual particles, but in this instance it was commingled with the alumsodium resinate precipitate. An important factor in each of these cases resides in the direct contact of the finely divided paraflin with the fibre by the direct deposition of the particles out of the emulsified state on to the fibre. These minute individual particles of paraflin are normally nonadhesive but there is a tendency under the conditions of agitation obtaining in the paper making process for some of the particles to become detached from the fibre, which particles may be agglomerated by pressure or otherwise so that relatively coarse flakes or lumps of paraffin are formed and exist at the wet end of the paper making machine. These flakes or lumps often cause very serious trouble particularly in the screens, in the web-forming device of the aper machine, and also in various parts 0 the machine clothing and the press rolls.

It has also been proposed heretofore to make waterproof paper such as roofing paper by mixing an emulsion of asphalt or the like, preferably containing clay as an emulsifying agent, with suitable fibre and running this mix off on a paper machine. These emultained in the felted sheet b more mechanical filtration the proportion o the emulsion used being sufiiciently great (sometimes equal to or greater than the amount of fibre present) to insure the retention of a sufficient amount of asphalt in the finished sheet. A modification of this process uses a fixin agent to attach the asphalt to the fibres. 6f course, apart from other reasons, because of their color the employment of as halt or bituminous emulsions is not feas1 le in making high grade book, magazine, writing or rinting' paper and the like. Moreover emu sions made with paraflin wherein solid emulsif ing agents such as clay are employed have een found to be disadvanta eous for the reason inter alia that when suc emulsions are employed in small quantities in a sheet such as might be expected to be sufiicient to produce a sized paper, the particle size of the paraffin is usually sufliciently large to cause waterproofing to occur in definite spots which are surrounded by areas that are substantially unsized, the finished product thereby resulting in a sheet having a combination of Waterproof areas and unsized or only partiall sized areas. Moreover emulsions made wit insoluble emulsifying agents have certain breakable characteristics as described below and have thus a tendency toward being broken during the pa er makin process with consequent deposition of para 11 or like material on various parts of the paper making machine and machine clothing.

For instance, some emulsions made with insoluble emulsifying agents have a tendency to be unstable at extreme dilutions. Such emulsions also may be sensitive to pressure, and also are known to be sensitive to the mechanical agencies em loyed in the paper making process such or example as the beater and the Jordan. Of course in these agencies there tends to be a contacting at high speed between two metal surfaces, and as is natural, this influence will tend to break down the insoluble particle film surrounding the individual particles of emulsified material, and consequent] numerous particles of the disperse phase aving their protective coating ruptured or removed will tend to coalesce and produce thereby larger or smaller lumps of unemulsified material which will cause trouble in the subsequent machining of the stock. It is therefore apparent that emulsions made with an insoluble emulsifying agent are not sufficiently completely rcsistant to the mechanical instrumentalities met with in the paper making process and thus they cannot be considered as substantially nonbreakable emulsions.

In my copending ap lication for Improvements in paper pro ucts and methods of making the same, Serial Number 262,030, filed March 15th, 1928, I have described a method of making a sized carbonate filled paper wherein a paraflin emulsion is. employed. In that application I have pointed out the necessity of obtaining as stable an emulsion as feasible, indicatin the particular necessity for this where ard water is to be used and/or where the fibrous constituents have not been washed sufiiciently to remove such soluble materials as may have a tendency to break the emulsion. Furthermore in that application I have disclosed the mutual flocculation of parafiin emulsions and carbonate fillers to give a unique carbonate filler parafiin complex.

Whereas the method I describe in the above referred to application is satisfactory in some cases, I have found that owing to the difliculty ofpreventing the premature breaking of the emulsions used it was desirable to find an emulsion which would be substantially nonbreakable under the conditions obtaining in paper making ractice up to the point of addition of the car onate filler. I have found such an emulsion and have also found that such a stable emulsion is not only stable to ordinary paper making procedure, but also is not mutually flocculated with carbonate filler as are the emulsions set out in m application Serial No. 262,030, mentione above.

Hence other means must be employed for per- 9 manently associating the emulsion with the paper mix, as will be described in detail be- My process consists broadly in adding to fibrous material, sodium resinate in a sufficient amount as indicated below and an emulsion of parafiin substantially nonbreakable by any of the chemical or mechanical agenc1es ordinarily employed in the paper making process in the concentrations or intensities in which they are normally used. Preferably after these are throughly mixed I then add alum, then carbonate filler. Prior to the addition of the carbonate filler, if a portion of the mix is withdrawn and made into a sheet in the laboratory, it will be found to be sized, but after the addition of the carbonate filler the mix gradually suffers a deterioration in sizing, although by the time the paper machine is reached there may still be some degree of sizing remaining in the stock in certain cases. However, I have discovered, that the sizing may be restored by the addition of tated with alum, and restored with a subsequent quantity of alum, in accordance with I .10,- course, I may, if I desire, use a greater uantity of sodium resinate, but it is to be pomted out that it is possible to secure satisfactory sizing by my process where there is not enough sodium resinate used to impart sizing .15 of itself.

As stated above, I have discovered that the use of emulsions which are substantially stable under normal paper making practice 'wholly avoids the numerous disadvantages as commonly encountered in prior processes involving the use of breakable emulsions. However, it will be apparent that the more use of substantially nonbreakable emulsions does not alone produce the desired results since unless suitable means are provided for effecting the association of such emulsions with the fibrous material they would merely pass off with the efiluent waters and not remain associated with the fibre as desired.

Ihave discovered that substantially nonbreakable emulsions can be brought into the desired association with fibres and held in -such association up to the desired point substantially without breaking the emulsions by concentrating the disperse phase ofthe emulsions by means of two mutually flocculating or precipitating materials, such for example as sodium resinate and alum. This concentration of the disperse phase in the concentrating precipitate however does not break the emulsion.

The fact that treatment in the manner suggested merely concentrates the disperse phase of the emulsion and does not break the emulsion is clearly shown by the followingexperiment: If a relatively dilute solution of sodium resinate is added to a breakable paraflin emulsion, such as saponaceous paraflin emulsion, and alum is then added in an amount sutficient to completely flocculate both the sodium resinate and the paraffin emulsion, there will result a precipitate and a clear residual liquid. The precipitate'will consist of an alum-sodium resinate precipitate and also of an alum-soap precipitate (that is, the soap which is used as the emulsi fying agent for the paraffin), and also individual particles of free paraflin released from the emulsified condition. Now if some chemical is added which completely dissolves these alum-sodium resinate and alum-soap compounds, (and which has been found at the concentration used and within the time required for the experiment will not of itself break the paraflin emulsion in question) such for example as sodium hydroxide, that part Up to this point the result appears to be ex-- actly the same as in the prevlous experiment. However, when sodium h droxide is added in the manner suggeste as above, in an amount sufiicient to dissolve the alum-sodium resinate compound, the entire solution becomes milky, no parafiin floats to the surface, and the paraflin emulsion is thus deconcentrated, i. e., restored to its original condition substantially unbroken. A microsco ic examination of the milky liquid shows tlibt the parafiln particles are present in the emulsified condition substantially the same as they were before the were concentrated by the precipitation o the alum-sodium resinate compound. It is apparent, therefore, that the action of the mutually flocculating materials in what appears to be the breaking of this emulsion is in no sense a breaking, but is an instance of the unique concentration of the disperse phase of a .substantially nonbreakable emulsion without the breaking of such emulsion. This concentration of the disperse phase is substantiall completely reversible, i. e., the dis erse p ase can be deconcentrated or 'dilute b dissolving the precipitate of the mutual y flocculating materials.

In other words in the concentrating precipitate, in this instance the alum-sodium resinate compound, the parafiin of a substantially nonbreakable emulsion does not exist as deposited particles released from emulsified form, and when the reaction is carried out in the presence of fibre the paraflin is not deposited jointly with the alumn-sodium resinate recipltate upon the fibre, and does not there ore cause the difliculties experienced in the paper making process, as is the case when breakable emulsions are broken with alum, either alone or in the presence of alumsodium resinate precipitate in the paper making process.

Moreover when the disperse phase of a substantially nonbreakable paraffin emulsion,

concentrated in an alum-sodium resinate precipitate on fibre, is subjected to the beating and jordaning operations in regular papermaking practice, although of course the concentrating recipitate may be mechanicall subdivided by these agencies, there is no evidence that any paraffin has been released from the emulsified condition, the concentrated disperse phase thus being apparently nonbreakable by the mechanical agencies to which it is subjected in the paper-making operation.

The alum-sodium resinate preci itate in the present instance, therefore, more y serves as a means for concentrating the disperse phase of an emulsion without breaking the emulsion, the disperse phase in the meantime being maintained in emulsified condition, and substantially nonbreakable by mechanical means. This concentration of the disperse phase appears to produce a complex which experiments indicate to be an intermediate between a true emulsion and a resolved or broken emulsion. For example, the complex can be temporarily dispersed by mechanical means as indicated above but not diluted in the true sense as in the case of true emulsions. However, the complex can in a sense be diluted by dissolving the mutually fiocculating agents therein and reconverting to a true emulsion. Thus while it is clear that the complex is not a true emulsion it is on the other hand, not a resolved emulsion. For example, the parafiin is not present in the concentrate as individual unitary deposited particles of parafiin, but rather in emulsified form, each particle being surrounded by a layer or film of emulsifying agent which prevents the individual particles from having contact not only with other particles of paraffin, but also from having contact with either the alum-sodium resinate precipitate, orthe fibres, or other constituents of the fibrous mix. The existence of the paraflin in emulsified form is thus continued throughout the entire wet end of the paper making process. It is associated with the solids in the paper mix but is not deposited as paraifin thereon, and thus, as heretofore stated, -completely elimidates the difiiculties which are present when emulsions are broken with alum, alone or in conjunction with sodium resinate, or by mechanical agencies, in the papenmaking process. This is a very great advance in the art of sizing paper with paraffin emulsions as will be readily appreciated by those skilled in the art.

As will be apparent to those skilled in the art, it is customary to employ substantially the following procedure in modern paper making practice: Fibrous materials together with filler, size, such as rosin size, size pre cipitant, such as alum, and coloring matter if desired, are ordinarily mixed in a beater or the like ata dry solid content of approximately 5 per cent. or slightly higher, and are subjected to a beating treatment in the beater, the amount of such treatment depending upon the type of paper which is to be made.

The paper mix is then ordinarily discharged from the beater and introduced into a container commonly called a beater chest, additional Water usually being added. Thereafter the mix is pumped from the beater chest to a suitable refining engine, usually a Jordan, at a dry solid content of approximately 4 per cent. In common practice the mix is usually diluted somewhat by the addition of water, and the diluted mix is ordinarily conducted from the Jordan to another container commonly known as a machine chest. From the machine chest the mix is pumped to a point near the web-forming end of the paper machine where it is largely diluted with water, water being added ordinarily in such an amount as to provide a dry content of from approximately of 1 per cent. or slight- 1y higher, but practically never in excess of 1 per cent. The mix in such highly dilute condition is then passed through rifilers or the like if desired and thereafter through screens and through the head box of the paper machine onto the machine wire or into the vat depending upon whether a Fourdrinier or a cylinder machine is employed, and during this passage additional amounts of water are usually added ,in the form of sprays or otherwise. This exact procedure is not always followed but in some instances is modified in accordance with the type of paper being made. For example, in the manufacture of certain types of paper, the beating process is almost or entirely dispensed with, the ingredients of the stock being merely mixed prior to jordaning. In some instances the step of refining or jordaning may be partially or wholly dispensed with. Moreover, the arrangement of the chests in respect to the mechanical treating apparatus is not in all cases precisely as described above.

.The time consumed from the point of mixing the ingredients in relatively concentrated state up to the point where the stock is to be diluted for delivery to the webforming end of the machine is relatively long in comparison with the time during which the stock exists in dilute condition prior to its delivery to the web-forming-end of the paper machine. The length of time during which the mix remains in a relatively con centrated condition may vary, of course, according to conditions, but it may be anywhere from as little as 15 or more minutes, as in certain extreme cases, up to a matter of a number of hours. On the other hand, the time during which the mix exists in a dilute stage prior to its delivery to the webforming end of the machine is in some cases a matter of only a few seconds and ordinarily not over a minute. Even under extreme conditions the time would never be in excess of 5 minutes.

In many instances the water supplied to the beater and also the water employed for dilution at the Jordan as well as for the final dilution of the mix before delivering to the web-forming end of the paper machine consists in whole or in part of white water by which term is meant to be included all effiuents from the web-forming end of the paper machine. It will be apparent therefore that this water functions cyclically in v the process and that there may be reintroduced into the earlier stages of the process part of the material which was derived from the web-forming stage of the process, such material being returned through the me- 10 dium of the white water.

Moreover in modern paper making practice there is a tendency to reclaim the ingredients contained in the white water, sometimes merely from that portion of it which is in excess of that which can be or is to be used cyclically in the process, or sometimes from a portion or from all of that which is to be used cyclically, or both, by subjecting the white water to some suitable procedure, as filtration, such for instance as deckering or actual passage through a filtering machine, or sedimentation or the like, thereby passing out the substantially purified aqueous efiluent to waste, or for further use in the pulp or paper making process, with the simultaneous return of the recovered material to the paper making process. In some installations this recovered material may be returned to the beater, while in others it may be returned to the beater chest, machine chest, or other point in the process if desired.

It will therefore. be apparent that independent of the exact type of apparatus and procedure employed, the following operations are normally employed in the paper making process; the mixing of the ingredients in relatively concentrated form; their contact in such concentrated form for a relatively long period of time; their subsequent dilution to a concentration suitable for delivery to the web-forming end of the paper machine; their remaining in such dilute condition a relatively short period of time; and the recontacting of the mixture of the ingredients prior to its delivery to the web-forming end of the paper machine with the cyclically returned white water and/or material recovered therefrom.

I have found as stated above that a mix made from fibrous materials, sodium resinate, a substantially nonbreakable parafiin emulsion, alum, and carbonate filler, gradually has its sizing deteriorated by the carbonate filler, the degree of deterioration varying with the time of contact and intimacy of contact of the carbonate filler with the rest of the mix.

I have also discovered, as stated above, that such a mix will have its sizing effect restored, thus producing a satisfactorily sized paper, if certain suitablematerials are added to the mix later in the paper making operation, at or subsequent to the point where the mix is largely diluted as described above prior to its delivery to the web-forming end of the paper machine. Thus the material constituting the sizing, the effect of which has been deteriorated or destroyed, acts as a potential sizing agent which is made effectual through the addition of a restoring relatively concentrated, and particularly,

when the relatively concentrated mix is subjected to agitation as is normal in the stock chests in paper making, that the restorative action is again destroyed. However, I have further discovered, if after applying the restorative action the mix is sub ected to a minimum degree of intimate contact and a minimum of time of contact, such as is the case when the mix is in dilute form prior to its delivery to the web-forming end of the paper machine, then the restorative action is ractically not affected or only slightly a ected according as the intimacy and/or time of contact may be lesser or greater. Also I have found that agitation in the dilute state has a very much less injurious effect than in the concentrated.

I have found in general that acidic material and/or salts of trivalent metals, such as ferric iron or aluminum, act as restorative agents. For example, I have found that it is possible to restore the sizing effects to a mix containing carbonate filler in which the sizing effect has been destroyed, by addition of an acid such as sulphuric acid (H 30 I have also found it possible to use acid salts such as sodium bisulphate (Nd-ISO However, the best agents I have so far found are the salts of the trivalent metals, such as ferric iron or aluminum, and of these aluminum has by my tests to date proven to be the better. Ferric iron may be used in papers other than white, but for white papers, of course, aluminum is the most suitable material, and even for colored papers, its relatively greater effectiveness may render it more economical.

Of the aluminum salts available the chloride, sulphate, or the like, or the double salts which are the true alums, may be used, but because of economy, the ordinary sulphate of aluminum normally known as alum is most suitable. I have found that any of the ordinary types of alum are satisfactory, whether acid, neutral, or basic. I have also found that whereas the acidic materials mentioned in the preceding paragraph can be used and although some of them are considerably cheaper than alum, that the effectiveness of alum seems to be sufliciently greater in proportion to the above mentioned materials, that it becomes economical to use alum instead of these relatively chea er materials.

Therefore the method I pre er to employ to restore the sizing consists substantial] of adding a subsequent portion of alum, re erably continuously, in the paper ma ing process as near as feasible to the point of web ormation on the paper machine preferably at or following the point at which the paper mix is largely diluted as indicated above.

The emulsions which I have found to be substantially unaffected by ordinary materials in the concentration at which they exist in the paper making process may be made in a variety of ways, for instance, with gums such as gum hatti or gum arabic. While dextrin of itse f does not appear to be suitable as an emulsifying agent, particularly if the emulsion is to be stored for any a preciable time, it does however appear to e useful in connection with the gums mentioned above. As the gums are normally much more expensive than dextrin, the dextrin may thus be used in conjunction with the gums to produce in general a lower cost emulsion. I

have tested several formulae involving the use of gums and dextrin which give emulsions of essentially the nature desired, and which I appear to work satisfactorily for the purpose. However, the one which I prefer to use in practice and which I have found to work well on a practical scale, is an emulsion made of paraflin with gum hatti and dextrin as emulsifying agents. 11 one such emulsion, for example which proved satisfactory, I used by weight as follows:

15 parts paraflin, 1 part gum ghatti, 1 part dextrin, 83 parts water.

As stated above so far as I have been able to discover by experiment, the emulsions which I employ are not affected in any way by any of the chemicals with which they come in contact at the concentrations 'at which they are used in the paper making process, nor are they affected b any of the mechanical agencies with whic they come in contact at the intensities at which they are normally employed in the paper making process.

The reason for this latter characteristic is probably that the particles in my emulsions are surrounded with a film as set forth previously which is one or more molecules in thickness and hence entirely of negligible thickness compared with any solid particle film. Hence such films cannot be knocked off or ruptured by ordina mechanical means, as the thickness of this fi hn is of entirely different order of magnitude (smaller) than are the clearances which obtain in the paper making machinery. This of course is not the case with emulsifiers of the insoluble type which possess much thicker films, whether the films so produced be made up'of individual particles of materials like clay, or whether they be of jelly-like character such as is the case where certain insoluble materials are employed which are of that character, whether introduced as one material or producer in situ by the reaction of the two or more materials.

Of course it is not necessary that the emulsifier I use be water soluble in the sense that sodium chloride, for instance, is soluble, as n'mterials which are known in the art as being colloidully soluble, are also suitable. For example gum ghatti which is suitable for my use may be considered to be in a measure colloidally soluble. V ith emulsifiers of the type I employ the condition of the layer surrounding the disperse phase is such that by mechanical action in the paper making process, this layer is not disrupted, and therefore, the emulsion remains substantially nonbreakable as heretofore indicated.

It is to be understood that I do not confine myself to the materials'indicated above as being suitable for my emulsion since now that the principle of the use of a substantially nonbreakable paraifin emulsion which is capable of having its disperse phase concentrated has been established in the paper industry, doubtless other similar emulsions will be evolved. Nor do I confine myself to the definite concentrati on of the paraflin in the emulsion nor to definite proportions of emulsifying agents to each other or to the araifin, as these ma be varied in considerab e degree without a ecting the desirable qualities of the emulsion.

Emulsions of the character referred to may be made in a variet of ways, as for example, in a dispersion mac ine such as any of a number of colloid mills or homogenizers. A suitable way is to melt the parafiin, dissolve the emulsifying agent or agents in water, heat the emulsifying agent solution abovethe melting point of the paraflin and then feed the melted paraflin and the heated solution of emulsifying agents jointly to the emulsifying machine.

In regard to the paraifin used, it is to be understood that either low or hi h melting point material can be employe The socalled fully refined paraffin is entirely satisfactory since it does not impart objectionable color to white sheets. However, for purposes of economy, it is often desirable to use a less pure material such for example as the material which is commonly known to the trade as semi-refined paraflin scale, containing approximately per cent. of oil and water as lmpurities, which material gives satisfactory results. Such material will perhaps in certain cases have varying meltlng points, but one particular sample used, for example, had a melting oint of approximately 115 F. (46 (3.). ther even more impure parafiins may be used, especially if the color (whiteness) requirements of the finished paper are not too exacting, or if papers, other than white, are to be made.

In the preferred practice of my invention I add to the beater or other similar or mixing or compounding or disintegratin or treating machine all the pulp or other brous materials to be employed except those coming under the definition of carbonate filler hereinafter set forth, and such fibrous material as is in the stock of the recovered white water. Thereafter I add sodium resinate, a substantially nonbrcakablc paraffin emulsion preferably in dilute form, and incorporate them thoroughly with the pulp. Alum is then added. After the sodium resinate-alum concentrating precipitate has been formed on the fibre I then add if desired fibrous materials coming under the definition of carbonate filler hereinafter set forth and/or carbonate filler itself. It is possible to add all the fibrous constituents and/or the carbonate filler itself in the beater prior to the addition of the alum but my experiments have indicated that better results are obtainable when the sodium resinate alum concentrating precipitate is formed on the fibre in the absence of any carbonate filler.

Moreover in furnishing the beater, I preferably use fresh water or white water which has been clarified so that the sodium resinate alum precipitate may be completely formed on the fibre before the addition of carbonate filler in any form to the mix.

In regard to the mixing of the ingredients of fibre (free from carbonate filler), and the other ingredients as indicated above, I do not confine myself strictly to the order of addition indicated above, but I have found that a suitable way is to allow sufiicient time for the sodium resinate and the substantially nonbreakable paraflin emulsion to be thoroughly incorporated with the fibre prior to the addition of the alum.

Furthermore, fillers of types other than carbonate fillers may be also added in the beater if it be desired to employ them in conjunction with the carbonate fillers in the paper, as well as coloring materials, and other substances which may normally be added in the paper making process.

In this connection, with the use of the carbonate filler, starch may be added, if de sired, to the mix in the heater or other point in the process, attention bein directed to my copending application Serial ITO. 202,453, filed June 29, 1927. The mix in the beater may then be given the usual treatment, passed through the beater chest, Jordan and machine chest. All waters used subsequent to the precipltation of the sodium resinate alum concentrating precipitate in the beater may be either fresh water or white water, as desired.

The mix still in relatively concentrated form is now at the point where it is ready for dilution preparatory to delivery to the web-forming end of the paper machine. Here the white water from the paper machine may be used as diluting water. At this point or subsequent thereto, alum is added preferably continuously, preferably in solution, the precaution being taken that adequate mixing of the alum, the whitewater and other water if used, and the relatively concentrated mix coming from the machine chest is insured. A. separate mixing box may be provided if desired but under ordinary machine practice this is unnecessary since there is usually adequate provision made in paper manufacturing to insure thorough mixing of the relatively concentrated mix with the diluting water. I have found in practice that it is also satisfactory to add the alum at a point subsequent to this, for example, just prior to the passage of the diluted mix to the screens, the screens affecting very thorough mixing in this case. If, however, the alum is actually added at the head-box of the machine subsequent to the screens, care should be taken that adequate distribution and mixing of the ingredients is' insured by proper bafiling or the like.

An illustrative furnish which may advantageously be used in practicing my invention is as follows:

Materials added in the beater Pounds Fibrous furnish (e. g. sulphite and soda ulps) 1700 R sin (added in the form of sodium res nate) l0 Parafiln (added in the form of substantially nonbreaknble paratlln emulsion) Alum rdinary A]g(S04)3.18H20) Catlipliungi carbonate magnesium hydroxide (carbonate Material added proportionately and continuoaslg on dilution Pounds Restoring agent, e. g. alum (ordinary (Al S0 .18H 0) 50 Another illustrative furnish is as follows:

Materials added in the beater Material added proportionately and continaouslg on dilution Pounds Restoring agent, e. g. alum (ordinary (Al SO .18H- O) 50 In the above formulae, the weights of carbonate filler refer to the bone dry basis, the weights of all other ingredients being given on the air dry basis.

In either of the above furnishes starch may be used. It may be conveniently added to the beater subsequent to the addition of the carbonate filler, or otherwise if desired. Suitable coloring matter may be added if desired.

The illustrative furnishes given above produce satisfactorily sized paper, and, as will be apparent, the sizing can be increased or decreased by varying the relative quantities of the materials used in the above formulee. The resultant paper may be used for such purposes as those to which sized papers are normally put including that asa raw stock for further conversion as for example for coating.

While 1 have described herein the effect of sodium resinate and alum as mutually precipitating agents to produce a concentrating efi'ect on the disperse phase of a substantially nonbreakable paraflin emulsion, other materials may be used, as for instance, soaps other than sodium resinate, or any partially or completely saponified material, such as saponified beeswax. Moreover, in place of alum as one of the mutually precipitating agents and as a sizing restoring agent of the character referred to, I may employ salts of other trivalent metals, such as ferric iron. Also, I may employ in place of ordinary alum other salts of aluminum, such as the chloride, or the like. In addition, sodium bisulphate may be employed with a certain measure of success.

When I employ the term paraffin herein, I mean paraflin wax, which is solid at ordinary or room temperature. I do not mean to restrict -myself only to the parafiin hydrocarbons, but mean to include in this term all the hydrocarbons of a waxy nature substantially unsaponifiable and inert to acidic and alkaline materials under ordinary conditions of temperature and pressure, whether derived from petroleum, shale, lignite, earth wax, or other natural or artificial sources. I do not, however, mean to include in this term material of a pitchy nature,.such as bitumen or asphalt.

By the term carbonate filler as employed herein is meant the substantially water insoluble normal or basic carbonates of alkaline earth metals (which expression is herein intended to include magnesium), or compounds, or double salts, or physically associated mixtures of these with one or more other acid soluble materials of a substantially water insoluble nature, these fillers whether simple or complex as above, being characterized by the fact that, when agitated in contact with freshly boiled distilled water in concentrated suspension for say an hour, they impart to the water a pH value which is on the alkaline side of the neutral point, and also by the fact that they give off carbon dioxide gas when brought into contact with an aqueous mineral acid, e. g. hydrochloric acid. Examples of such fillers are calcium carbonate, of which lime mud from the causticizing process is one form; calcium carbonate magnesium basic carbonate employed in the paper disclosed in my U. S. Patent No. 1,595,416 of August 10, 1926; and calcium carbonate magnesium hydroxide disclosed in my U. S. Patent N 0. 1,415,391 of May 9, 1922. As will be apparent, these fillers are referred to not only in their chemically pure form but also in commercial form containing such impurities as may occur in such commercial products;

and also when present with other material, so that they constitute only a part, either major or minor, of the whole. It should be stated that any given filler of the type referred to is not necessarily of uniform particle size; nor are the average particles sizes of the fillers necessarily alike, as some of the fillers of the type referred to have relatively coarse grain particles, whereas others are much more finely divided, and some are so finely divided that they may be said to approach or be in the colloidal condition.

Moreover, by the term carbonate filler, I mean to include not only the case where the carbonate filler is added as such in the paper making process, but also the case where 1 it may be added wholly or in part incorpo-' rated with fibrous material and/or other material such as paper coating constituents or the like. Such a case would be where paper made with carbonate filler, either as a filling or coating constituent, or both is reused in the paper making process. Such papers may be those known to the trade as old papers or old waste papers or waste papers in any form, or returned trimmings or damaged paper or the like, or they may be the broke, that is, the partially made, the imperfect, or the waste paper which accompanies the paper making, finishing, storing, packing, shipping, or the like operations in a paper mill, and which is reworked either in the same or some other mill. Such papers are sometimes reworked by themselves and added in broken down or in pulp form in the paper making process, being treated or cooked in some cases With or without chemicals and washed if desired, this reworking meaning to include the process of deinking if such is practiced or of bleaching or of both deinking and bleaching, or sometimes they are added directly in the paper making process and broken down to pu'lp form therein. In any event they are a source of carbonate filler in the paper to be made, and are included in the term carbonate filler as used herein. When I use the word paper herein, I use it in the broad sense to include products of manufacture of all types and of all weights and thicknesses, which contain as an essential constituent a considerable amount of prepared fibre and which are capable of being produced on a Fourdrinier, cylinder, or other forming, felting, shaping or molding machine.

Although the expression wet end of the paper machine may at times be used to convey various meanings, where I use the expression in the claims I intend it to include those instrumentalities provided in paper manufacture by which and/or in which the relatively concentrated mix is diluted, and treated, conveyed or fed up to the point of web formation, such as the box, regulatin and proportioning1 devlces, r filers, trougfiis, screens machine cad boxes, 1n le ts, and the like, including also instrumentahties used in the white water 0 cle, but I do not intend to include in this efinition the webforming device itself that is, the moving wire in the case of a F ourdrinier machine or the cylinder mold in the case of a cylmder machine.

Although I have described in detail several illustrative furnishes I do not intend to be limited thereby, as my invention may be practiced with a broad variety of formulae, using various materials customarlly employed for various grades of paper in any suitable proportions. Moreover, various changes in procedure, ingredients, and arrangement of steps may be resorted to in the ractice of my invention without departing cm the spirit of my invention or the scope of the subjoined claims.

I claim:

1. The method of manufacturing a sized pager filled with carbonate filler comprising ad ing to fibrous material a substantially nonbreakable parafiin emulsion and a substance which will react with a second substance subsequently added to form a precipitate, adding said secondsubstance, the reaction caused thereby serving to concentrate the disperse phase of said paraflin emulsion but not to break said emulsion, adding carbonate filler, thereafter adding a sizing restoring agent under conditions favoring the minimizing of the time of contact of the constituents of the mix, and thereafter making paper therefrom.

2. In a method of manufacturing a sized paper filled with carbonate filler, the step of adding to a paper mix containing carbonate filler which paper mix has been previously sized by concentratin thereon the disperse base of a substanti y nonbreakable parafemulsion by the precipitation of two mutually reacting substances, a sizing restoring agent under conditions favorin the minimizing of the time of contact of t e constituents of the mix.

3. The method of manufacturing a sized pa r filled with carbonate filler comprising ad 'ng to fibrous material a substantially nonbreakable paraflin emulsion and a substance ca able of reactin with a second substance su sequently adde l to form a precipitate upon the fibrous material, adding said second substance, the reaction caused thereb serving to concentrate in association with said precipitate the disperse, phase of said parafiin emulsion but not to break said emulsion, said precipitate being substantially incapable 0 having the paraflin associated therewith released from emulsified condition by mechanical means, adding carbonate filler, thereafter adding a sizing restoring agent under conditions favoring the minimizing of the time of contact of the constituents of the mix, and thereafter making paper therefrom.

4. The method of manufacturing a sized paper filled with carbonate filler comprising adding to fibrous material a substantially nonbreakable parafiin emulsion and a substance which will react with a second substance subsequently added to form a precipitate, adding said second substance, the reaction caused thereby serving to concentrate the disperse phase of said parafiin emulsion but not to break said emulsion, adding carbonate filler, thereafter adding a salt of a trivalent metal under conditions favoring the minimizing of the time of contact of the constituents of the mix, and thereafter making paper therefrom.

5. The method of manufacturing a sized paper filled with carbonate filler comprising addingto fibrousmaterial a substantially nonbreakable parafiin emulsion and a substance which will react with a second substance subsequently added to form a precipitate, adding said second substance, the reaction caused thereby serving to concentrate the disperse phase of said parafiin emulsion but not to break said emulsion, adding carbonate filler, thereafter adding a salt of aluminum under conditions favoring the minimizing of the time of contact of the constituents of the mix, and thereafter making paper therefrom.

6. The method of manufacturing a sized paper filled with carbonate filler comprising adding to fibrous material a substantially nonbreakable paraflin emulsion and a substance which will react with a second sub stance subsequently added to form a precipitate, adding said second substance, the reaction caused thereby serving to concentrate the disperse phase of said parafiin emulsion but not to break said emulsion, adding carbonate filler, thereafter adding alum under conditions favoring the minimizing of the time and intimacy of contact of the constituents of the mix, and thereafter making paper therefrom.

7. The method of manufacturing a sized I pager filled with carbonate filler comprising ad ing to fibrous material a substantially nonbreakable paraflin emulsion and a substance which will react with a second substance subsequently added to form a recipitate, addin said second substance, t e reaction causef thereby serving to concentrate the disperse phase of said parafiin emulsion with the disperse bonate filler, which paper mix has been previously sized by concentrating thereon the disperse phase of a substantially nonbreakable parafiin emulsion by the precipitation of two mutually reacting substances, a salt of a trivalent metal under conditions favoring the minimizing of the time of contact of the constituents of the mix.

9. In a method of manufacturing a sized paper filled with carbonate filler, the step of adding to a paper mix containing carbonate filler, which paper mix has been previously sized by concentrating thereon the disperse phase of a substantially nonbreakable paraffin emulsion by the precipitation of two mutually reacting substances, alum under conditions favoring the minimizing of the time and intimacy of contact of the constituents of the mix.

10. The method of treating a paper mix originally containing carbonate filler and fibrous material having incorporated therewith the disperse phase of a substantially nonbreakable parafiin emulsion in association with the precipitate produced byatwo mutually reacting substances, comprlsing adding to such mix a salt of a trivalent metal at the wet end of the aper machine. 1;

11. The met 0d of treating a paper mix originally containin carbonate filler and fibrous material havmg incorporated therehase of a substantially nonbreakable para 11 emulsion in association with the precipitate produced by two mutually. reacting substances, comprising adding to such mix alum at the wet end of the pa r machine.

12. he method of manufacturing a sized paper filled with carbonate filler comprising mixin with fibrous material a substan- "tially non reakable paraflin emulsion, sa-

nified material, a precipitant therefor, and carbonate filler, thereafter adding a s zing restoring agent under conditions favorin the mimimizing of the time of contact 0 the constituents of the mix, and thereafter passing the mix on to a web-forming device.

13. The method of manufacturing a sized paper filled with carbonate filler comprising mixing with fibrous material a substantially nonbreakable paraflin emulsion, saponified material, a precipitant therefor, and carbonate filler, thereafter addin a sizing restoring agent at the wet end of t e paper machine, and thereafter making paper therefrom.

14. The method of manufacturing a sized paper filled with carbonate filler comprising mixing with fibrous material a substantially nonbreakable paraflin emulsion, saponified material, a precipitant therefor, and carbonate filler, thereafter adding alum at the wet end of the paper machine, and thereafter making paper therefrom.

15. The method of manufacturing a sized paper filled with carbonate filler comprising mixing with fibrous material a substantially nonbreakable parafiin emulsion, soap, a preci itant therefor, and carbonatefiller, thereafter adding alum at the wet end of the paper machine, and thereafter making paper therefrom.

16. The method of manufacturing a sized paper filled with carbonate filler comprising mixing with fibrous material a substantially nonbreakable paraflin emulsion, sodium resinate, a precipitant therefor, and carbonate filler, thereafter adding alum at the wet end of the paper machine, and thereafter making paper therefrom.

17. The method of manufacturing a sized paper filled with carbonate filler comprising mixing with fibrous material a substantially nonbreakable parafiin emulsion, sodium resinate, alum, andcarbonate filler, thereafter adding alum at the wet end of the paper machine, and thereafter making paper therefrom.

18. he method of manufacturing a sized paper filled with carbonate filler comprising mixing with fibrous material a substantially nonbreakable paraflin emulsion, sodium resinate in an amount insuificient of itself to impart a substantial degree of sizing to the paper, alum, and carbonate filler, thereafter adding alum at the wet end of the paper machine, and thereafter making paper therefrom.

19. The method of manufacturing a sized paper filled with carbonate filler comprising mixing with fibrous material a parafiin emulsion made with gum ghatti as emulsifying agent, sodium resinate, alum, and carbonate filler, thereafter adding alum at the wet end of the paper machine, and thereafter making paper therefrom.

20. The method of manufacturing a sized paper filled with carbonate filler comprising mixing with'fibrous material a substantially nonbreakable paraflin emulsion made with gum ghatti and dextrin as emulsifying agents, sodium resinate, alum and carbonate filler, thereafter adding alum at the wet end of the paper machine, and thereafter making paper therefrom.

21. A. sized paper comprising fibrous material, carbonate filler, the reaction product of sodium resinate and alum, said sodium resinate having been originally present in an amount insuflicient of itself to impart a substantial degree of sizing to the paper, and paraflin.

In testimony whereof I aifix my signature.

HAROLD ROBERT RAFTON. 

